But you just explained exactly the problem: they work as a first strike. They work as a "surprise we're doing it". But they don't create a tactical military adv

But you just explained exactly the problem: they work as a first strike. They work as a "surprise we're doing it". But they don't create a tactical military advantage...however they will absolutely massacre nearby civilian populations and non-combatants. Zone Rouge isn't full of chemical shells, it's full of everything - just general unexploded ordnance. Chemical shells in WW1 also did not cause "hundreds of thousands of deaths" - the highest estimate is about 90,000 deaths and 1.3 million casualties[1] Same story with the use of chemical irritants: while they worked on the gas masks of the time, they don't work today and they weren't particular efficacious. And you've identified again, the obvious problem: clouds of chemical gas in the air will affect your own troops just as much as the enemy. Which loops around to the basic problem: two military's can have a fun chemical weapon exchange on the battlefield, and accomplish basically nothing when properly equipped: with appropriate counter-measures the shells don't do anything, they leave people, equipment and fortifications intact. But the wounded? Nearby civilians? Anyone downwind who wasn't properly informed friendly forces are deploying chemical weapons? The weather changing unexpectedly? They're all going to be wounded or die from that. They are tactically ineffective compared to conventional weapons versus any force prepared to face them, and they are sufficiently easily produced that they do not represent a substantial advantage. Not to mention other basic problems - like your own munitions stores now not just exploding, but exploding and releasing a fast moving, possibly persistent toxin - or worse, being damaged and slowly leaking your VX nerve gas into a cloud which takes out your logistics base and the frontline guys rotating back, and then leaves all your stores intact for the enemy to retrieve when they turn up later and it's dissipated. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2376985/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2376985/